Polishing wheel



D. F. McGOVERN.' POLISHING-WHEEL. APPLICATION FILED-MAY is. 1921.

' Ihvezz t or Patented May 23, 1922.

DanielEM 'oygrn DANIEL 1F. IlECG'QVEBN, OF MONCEPELIER, VERMONT.

POLISHING \VHEEL.

Application filed May 13, 1921.

T 0 all to ham it may concern Be it known that DANIEL F. McGovern, a citizen of the United States, residing at Montpelier, county of Washington, State of Vermont, has invented certain new and useful Improvements in Polishing lVheels, of which the following is a specification.

My present invention relates to certain improvements in stone polishing wheels and particularly to those wheels for imparting the initial polish to a stone surface by an abrasive such as chilled shot, as distin guished from emery polishing.

As illustrative of my invention .l have shown one of my wheels, the same being in its general form the type shown in my prior Patent No. 1,296,985, of March 11, 1.919. In this wheel a great practical advantage was gained in the use of two sets of concentric flanges of substantially semicircular extent, each set being offset slightly on the cover disc or plate which is characteristic of this type of wheel.

The construction referred to has proven very advantageous in that it embodies long continuous flange surfaces of great feeding capacity as well as of great efflcicncy in their oscillating movement which is the working movement effecting the abrasive action on the stone.

The great difficulty, however, in all wheels of this type has been to secure a propor tioning of the two opposed factors in the movement of the abrasive under the wheel. These two movements should be considered as they underlie the principles of my pres ent invention.

It will be seen that ina mu -h tllese wheels must feed or draw tl e -.bra"lve i--- ward to have it available fo' the workin j edges of the fl gee. there must be a co.-- stant tendency of the material to travel in ward towards the center of the wheel, At the same time the abrasive when under flanges has a tendency to work out, due to the rotative action of the wheel as a whole. The movement of the body of abrasive is therefore a double movement and as these tendencies are opposed, it is of the greatest importance that they be balanced in so far as possible so as to secure a maximum of efficiency through equality of distribution.

()ne other factor must furthermore be Specification of Letters Patent.

Patented 23, 1 1922.

Serial No. 469,094.

noted before passing to the discussion of my present invention. This factor is that of the variable speed of different portions of the wheel considered radially. That is to say, the outer portions of the wheel travel at a rapid rate while the inner portions of the wheel nearer the center have comparatively slight movement. This has caused in a great many commercial wheels, a choking tendency near the center which has prevented the operation of the wheel and necessitated frequent over turnings in order to dislodge the shot and mud from the channels in which it has become packed.

As illustrative of my invention I have endeavored to show in the accompanying drawings, a structure of my present improvement and to illustrate its action and the above mentioned theory in a necessarily somewhat diagrammatic manner. Throughout the specification and drawings the usual reference characters are applied to represent corresponding parts, and in the drawings Fig. lis a section through adjacent flanges showing the action of the shot during rotation,'and

Fig. 2 is a face view of the wheel in accordance with my invention.

Referring to the wheel shbwn in my drawings it will be noted in general that there are two sets of substantially concentric half circle flanges 4:, 5, 6, 7 and 8, and t, 5, 6. T and 8. These sets are slightly off center with regard to the central aperture 2 in the plate 1 to which the flanges are at tached and which overlies and gives draft to the wheel.

Furthermore, characteristic of this wheel it will be noted that the two flanges o. constitute in reality feeders whose first and immediate function is to draw in asive from the edge of the wheel by the action of their runner shaped ends a, passing it along to the channels 6, 7' and 8' which are in the opposite set. Of course it will be understood that all of the flanges at all times are supposed to have their working edges acting on the abrasive which while rolling along the flanges for certain distances eventually is worked out by the centrifugal action towards the edge of the wheel. The body of the shot, however, works inwardly,

of the wheel I am able to secure a return at being scooped by the inner faces oi. the flanges as it is passed inward.

in order to assure an adequate supply to the inner portions oi the wheel, this body of shot within. the channels must of necessity be somewhat in excess o'l. the amount actually required to cover the surface of the work under the flanges. The result therefore is that there is certain at times to be a considerable excess of: shot passed into the central channels of the wheel which unless otherwise accon'imodated chokes the channels as before described.

I have discovered that by reason ot the relatively lower speed ot the inner regions this excess of abrasive by simply providing interruptions or openings in the iower edges of the interior flanges through which excess abrasive may pass radially outward to the feed flanges and thus circulate within the wheel itself without danger of clogging and assuring at all times ample amounts of abrasive adjacent the channel edges in all portions of the wheel.

I have shown in the drawings such apertures indicated at A. In the specific form shown these are cut through the flanges t3 and 7 and 6 and 7 in slightly staggered relation. I have indicated by the arrow .7 the inward Feed of the abrasive and by the arrow Y the outward movement of excess ab *asive through the apertures A. 80 constructed the efliciency of the wheel is very materially increased and its workingca pacity very much enlarged. Th apertures should be somewhat proportioned to the diameter of the wheel and their number may possibly be aried, although I find that a single aperture in each oi the two flanges mentioned in my own wheel. seems to give maximum etliciency.

My invention may be applied to a variety of types of wheel. but is I believe. especially effective in such a wheel as that shown in which there are long substantially continucus feeding flanges delivering to an interior group of work flanges of substantially continuous character and whose action is 1,41 spree slightly eccentric to the rotation of the Wheel on its axis.

.Vhat I therefore claim and desire to se cure by .Letters Patent is:

1. A polishing wheel comprising a plate having on its working face a plurality of spaced flanges, the space between the outer flair of flan 'es detinin an uninterru )ted abrasire feed channel and an inner pair of flanges included by said outer pair having openings between their ends for the radial return of the abrasive to said feed channel, the opening in one of said flanges being staggered with relation to the opening of the other flange. V r

2. A polishing wheel comprising a plate having on its working face a plurality of spaced flanges the space between the outer pair of flanges defining anuninterrupted abrasive feed channel and an inner pair of flanges included by said outer pair having open ngs be ween their ends terminating short of the under tare oi the plate and permitting the radial return of the abrasive to said :t'eed channel. the opening in one ou said flanges being re'ered with relation to the opening oi the other flange.

5-3. A polishing wheel comprising a plate harin on its working taee duplicate sets of spaceo substantiaily concentric segmental I said sets being relathe centers 0! tively ofl'set. and the spaces between the outer pair o2? flanges of each set defining uninterrupted abrasive feed channels progressing towards the center oi": the plate, a pair the "s oi each setincluded by said outer pa 5 r o t fl a ages having openings between their ends for the radial return of the abrasive to said teed channels. and the opening in one flange o'" each pair being latively staggered with r -..'ion to the ope. -ig in the adjacent flange 01" said flange pair.

In testimony whereof I my signature in presence of two witnesses.

DANIEL F. MoGOVERN.

Witnesses Bonner E. LYons, EVELYN M. ALDEN. 

